The present invention relates to combinatorial complex carbohydrate libraries and methods for the manufacture and use thereof and, more particularly, to such libraries prepared on a solid support via stepwise enzymatic synthesis, to thereby provide a combinatorial array of complex carbohydrate structures. The combinatorial complex carbohydrate libraries synthesized according to the present invention can be exploited in a variety of ways, including, but not limited to, (i) identification of complex carbohydrate drugs; (ii) identification of complex carbohydrate associated receptors or proteins as potential new carbohydrate related targets for drug therapy; (iii) identification of biologically-active complex carbohydrates; (iv) identification of specific complex structural carbohydrate elements as potential new targets for drug therapy; (v) identification of the active sites of known complex carbohydrate structures; (vi) identification of new glyco-markers in complex carbohydrate structures; and (vii) detection of antibodies formed against a cancer-related glyco-epitope or other disease related glyco-antigens.